746 research outputs found
α5β1-Integrin promotes tension-dependent mammary epithelial cell invasion by engaging the fibronectin synergy site.
Tumors are fibrotic and characterized by abundant, remodeled, and cross-linked collagen that stiffens the extracellular matrix stroma. The stiffened collagenous stroma fosters malignant transformation of the tissue by increasing tumor cell tension to promote focal adhesion formation and potentiate growth factor receptor signaling through kinase. Importantly, collagen cross-linking requires fibronectin (FN). Fibrotic tumors contain abundant FN, and tumor cells frequently up-regulate the FN receptor α5β1 integrin. Using transgenic and xenograft models and tunable two- and three-dimensional substrates, we show that FN-bound α5β1 integrin promotes tension-dependent malignant transformation through engagement of the synergy site that enhances integrin adhesion force. We determined that ligation of the synergy site of FN permits tumor cells to engage a zyxin-stabilized, vinculin-linked scaffold that facilitates nucleation of phosphatidylinositol (3,4,5)-triphosphate at the plasma membrane to enhance phosphoinositide 3-kinase (PI3K)-dependent tumor cell invasion. The data explain why rigid collagen fibrils potentiate PI3K activation to promote malignancy and offer a perspective regarding the consistent up-regulation of α5β1 integrin and FN in many tumors and their correlation with cancer aggression
Pressure shift of the superconducting T_c of LiFeAs
The effect of hydrostatic pressure on the superconductivity in LiFeAs is
investigated up to 1.8 GPa. The superconducting transition temperature, T_c,
decreases linearly with pressure at a rate of 1.5 K/GPa. The negative pressure
coefficient of T_c and the high ambient pressure T_c indicate that LiFeAs is
the high-pressure analogue of the isoelectronic SrFe_2As_2 and BaFe_2As_2.Comment: 3 pages, 2 figure
Contrasting Pressure Effects in Sr2VFeAsO3 and Sr2ScFePO3
We report the resistivity measurements under pressure of two Fe-based
superconductors with a thick perovskite oxide layer, Sr2VFeAsO3 and Sr2ScFePO3.
The superconducting transition temperature Tc of Sr2VFeAsO3 markedly increases
with increasing pressure. Its onset value, which was Tc{onset}=36.4 K at
ambient pressure, increases to Tc{onset}=46.0 K at ~4 GPa, ensuring the
potential of the "21113" system as a high-Tc material. However, the
superconductivity of Sr2ScFePO3 is strongly suppressed under pressure. The
Tc{onset} of ~16 K decreases to ~5 K at ~4 GPa, and the zero-resistance state
is almost lost. We discuss the factor that induces this contrasting pressure
effect.Comment: 5 pages, 4 figures, to be published in J. Phys. Soc. Jpn. No.12
(2009
Characterisation of an n-type segmented BEGe detector
A four-fold segmented n-type point-contact "Broad Energy" high-purity
germanium detector, SegBEGe, has been characterised at the Max-Planck-Institut
f\"ur Physik in Munich. The main characteristics of the detector are described
and first measurements concerning the detector properties are presented. The
possibility to use mirror pulses to determine source positions is discussed as
well as charge losses observed close to the core contact
Interplay of Superconductivity and Fermi-Liquid Transport in Rh-Doped CaFe2As2 with Lattice-Collapse Transition
Ca(FeRh)As undergoes successive phase transitions with
increasing Rh doping in the 0 limit. The antiferromagnetic-metal phase
with orthorhombic structure at 0.00 0.020 is driven to a
superconducting phase with uncollapsed-tetragonal (ucT) structure at 0.020
0.024; a non-superconducting collapsed-tetragonal (cT) phase
takes over at 0.024. The breakdown of Fermi-liquid transport is
observed in the ucT phase above . In the adjacent cT phase,
Fermi-liquid transport is restored along with a disappearance of
superconductivity. This interplay of superconductivity and Fermi-liquid
transport suggests the essential role of magnetic fluctuations in the emergence
of superconductivity in doped CaFeAs.Comment: 11 pages, 4 figure
Abell 1451 and 1RXS J131423.6-251521: a multi-wavelength study of two dynamically perturbed clusters of galaxies
We present results from optical, X-ray and radio observations of two X-ray
bright (L_X ~ 10^{45} erg/s) galaxy clusters. A1451 is at redshift z=0.1989 and
has line-of-sight velocity dispersion sigma_v = 1330 km/s as measured from 57
cluster galaxies. It has regular X-ray emission without signs of substructure,
a Gaussian velocity distribution, lack of a cooling flow region and significant
deviations from the observed scaling laws between luminosity, temperature and
velocity dispersion, indicating a possible merging shock. There is only one
spectroscopically confirmed cluster radio galaxy, which is close to the X-ray
peak. 1RXS J131423.6-251521 has z=0.2474 and sigma_v = 1100 km/s from 37
galaxies. There are two distinct galaxy groups with a projected separation of
\~700 kpc. The velocity histogram is bi-modal with a redshift-space separation
of ~1700 km/s, and the X-ray emission is double peaked. Although there are no
spectroscopically confirmed cluster radio galaxies, we have identified a
plausible relic source candidate.Comment: 16 pages, 12 figures, some in colour; A&A accepte
Natural language analysis of online health forums
Despite advances in concept extraction from free text, finding
meaningful health related information from online patient forums
still poses a significant challenge. Here we demonstrate how structured
information can be extracted from posts found in such online health related
forums by forming relationships between a drug/treatment and a
symptom or side effect, including the polarity/sentiment of the patient.
In particular, a rule-based natural language processing (NLP) system
is deployed, where information in sentences is linked together though
anaphora resolution. Our NLP relationship extraction system provides
a strong baseline, achieving an F1 score of over 80% in discovering the
said relationships that are present in the posts we analysed
Pressure-induced superconductivity in Iron pnictide compound SrFe2As2
Electrical resistivity under high pressure have been measured on nominally
pure SrFe2As2 up to 14 GPa. The resistivity drop appeared with increasing
pressure, and we clearly observed zero resistivity. The maximum of
superconducting transition temperature (Tc) is 38 K. The value is corresponding
to the one of optimally doping AFe2As2 (A=Sr, Ba) system with K+ ions at the
A2+ site.Comment: 10 pages, 2 figure
An integrated Pan-European perspective on coastal Lagoons management through a mosaic-DPSIR approach
© The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 6 (2016): 19400, doi:10.1038/srep19400.A decision support framework for the management of lagoon ecosystems was tested using four European Lagoons: Ria de Aveiro (Portugal), Mar Menor (Spain), Tyligulskyi Liman (Ukraine) and Vistula Lagoon (Poland/Russia). Our aim was to formulate integrated management recommendations for European lagoons. To achieve this we followed a DPSIR (Drivers-Pressures-State Change-Impacts-Responses) approach, with focus on integrating aspects of human wellbeing, welfare and ecosystem sustainability. The most important drivers in each lagoon were identified, based on information gathered from the lagoons’ stakeholders, complemented by scientific knowledge on each lagoon as seen from a land-sea perspective. The DPSIR cycles for each driver were combined into a mosaic-DPSIR conceptual model to examine the interdependency between the multiple and interacting uses of the lagoon. This framework emphasizes the common links, but also the specificities of responses to drivers and the ecosystem services provided. The information collected was used to formulate recommendations for the sustainable management of lagoons within a Pan-European context. Several common management recommendations were proposed, but specificities were also identified. The study synthesizes the present conditions for the management of lagoons, thus analysing and examining the activities that might be developed in different scenarios, scenarios which facilitate ecosystem protection without compromising future generations.This study was supported by the European Commission, under the 7th Framework Programme, through the collaborative research project LAGOONS (contract n° 283157); by European funds through COMPETE and by Portuguese funds through the national Foundation for Science and Technology – FCT (PEst-C/MAR/LA0017/2013). The post-Doc grant SFRH/BPD/41117/2007 (M Dolbeth) and the PhD grant SFRH/BD/79170/2011 (LP Sousa) supported by FCT are also acknowledged
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